Could you tell me how I can loosen the screws within the slide of the KJW USP Tactical. The screws fasten the rear sights to the slide but I've mustered all the strength in me to make those things budge. Much to my shigrin they are on the way to being stripped. I need help. If anyone knows how to transplant the metal kit into the Tactical and can step by step tell me then that'd be great. Thank you.